UPDATED: After years of seeing its rivals dominating highlights and fantasy football, the NFL Now app seeks to compete in the mega-billion-dollar market of "companion content."

Two years ago, the NFL brought together its executives and consultants to figure out how it could muscle into the world of digital apps. The league's own research had shown that 56 percent of its TV viewers use a computer, tablet or phone while watching games, yet the "second screen" experience was being dominated not by the NFL but by the likes of Yahoo, ESPN and dozens of other aggressive outlets.

"We looked at how our fans' consumption is evolving," says Chris Halpin, the NFL's vp media strategy and business development. "And we saw an opportunity to meet a growing demand for video content cross-platform."

The new app became available Wednesday night in advance of the NFL regular season which kicks off Sept. 4. NFL Now is the new digital home for everything the league shoots, edits and collects in real time -- except live games, which are shared among CBS, Fox, NBC and ESPN and are so valuable that AT&T has threatened to cancel its $48.5 billion acquisition of DirecTV if the NFL Sunday Ticket package is not renewed. The NFL Now app puts the league and its 32 owners in direct competition with the sports broadcasters and news outlets that have built lucrative businesses on its highlights and fantasy stats. Content on the free app is personalized for fans, and a premium service expected to cost $2 to $3 per month will grant access to past games, highlights from the NFL Films library and content from the league-owned NFL Network.

It's the biggest online push yet (sources peg the investment at tens of millions of dollars) for a league that dominates TV ratings and revenue in the U.S. but has lagged in the digital domain. Major League Baseball boasts 10 million downloads of its At Bat app, which offers live streams of some games, and the NBA is behind three of the top 12 sports apps, according to iTunes. Those leagues are joining a new digital network from Time Inc. called Time 120 that mixes news and social media about baseball, basketball and hockey -- but not football, which has offered only limited content on NFL.com. "The NFL has tended to go it alone on virtually everything," says Daniel Durbin, director of USC's Annenberg Institute of Sports, Media and Society. "They know they're the dominant dog in the U.S. and want to keep it that way. They don't want to give the impression they are beholden to anyone."

To hook users, NFL Now takes a page from Netflix, Amazon and others by personalizing content and offering recommendations based on usage. Once preferred teams and players are identified, the app generates clips, news and game highlights specific to the fan. The free version of the app will have commercials (charter sponsors include Verizon, Gillette, McDonald's and Nationwide), and an international version will offer some full games in an effort to grow the sport overseas.

Durbin believes the NFL can turn the app into a major revenue driver, and that its biggest goal could be to gain more influence over the estimated $11 billion fantasy football market. More than 32 million Americans participated in fantasy leagues in 2011, according to Stats LLC, with 74 percent involved with NFL football. Yet the NFL sees little of that revenue. After decades of failed lawsuits seeking to control the stats, NFL Now is the most aggressive effort by league owners to compete in the fantasy business. "In the technological age, to control the streams of information is to control the money," adds Durbin. "For the first time, they can make inroads into owning the data fantasy leagues use."

While there are dozens of second-screen choices offering football-related content, the NFL believes its brand identity and unique content will be the game changer. "To use a football analogy, we're still in the first quarter of all this," says John Fletcher, senior analyst at SNL Kagan. "People are still experimenting, trying to see what works. The important thing is to be where your audience wants to be and on the devices they want to use, and so I think [NFL Now] is a good move."